Rise of Turbine Inlet Temperature plays a significant role to improve thermal efficiency of GTCC. MHI Group participates in Japanese National Project since 2004; "Development of 1700 °C class gas turbine components technology". Advanced TBC developed through the project has been succeeded in field operations of 1600 °C class gas turbine. Still; it is necessary to improve thermal insulation ability more to achieve higher turbine inlet temperature. Advanced TBC was assessed to be capable for thicker for various components test. Following the components development; hot parts sprayed with the thicker advanced TBC were verified in real operation. In conclusion; the advanced TBC developed in the project has excellent durability; which allows being thick enough to contributes the development of 1650 °C class JAC gas turbine. Consequently; MHI Group has succeeded in verifying JAC gas turbine in 2020. MHI is keep testing it in JAC gas turbine demonstration facility for long-term reliability.